WEBVTT

1
00:00:00.512 --> 00:00:02.816
Hi everyone it's Mal Abbott from PV lighthouse

2
00:00:03.072 --> 00:00:07.936
And in this next video we're going to take a look at how we can take the optical results from SunSolve

3
00:00:08.192 --> 00:00:09.984
And convert those into electrical output

4
00:00:12.288 --> 00:00:17.152
The contents of this video is 3 parts the first part we're going to have a look at an overview

5
00:00:17.408 --> 00:00:21.248
Of how to link SunSolve's optical output to various types of electrical solvers

6
00:00:21.760 --> 00:00:25.600
Then we're going to focus in on the SunSolve electrical solver itself and how that works

7
00:00:26.624 --> 00:00:29.696
Finally we'll go across to the software itself and have a look at

8
00:00:30.208 --> 00:00:32.768
Where in the user-interface we would set the different inputs

9
00:00:33.024 --> 00:00:34.048
For the electrical solver

10
00:00:35.840 --> 00:00:40.192
You may like to use SunSolve-Power for the optical loss analysis

11
00:00:40.704 --> 00:00:43.776
And then use it's output in a different electrical solver

12
00:00:44.544 --> 00:00:47.616
This might commonly be done with programs such as Quokka

13
00:00:47.872 --> 00:00:49.408
Pc1d or Griddler

14
00:00:49.664 --> 00:00:50.432
And we have

15
00:00:50.688 --> 00:00:51.968
Dedicated output

16
00:00:52.224 --> 00:00:54.528
Functionality for each of these programs

17
00:00:55.040 --> 00:00:56.064
The way this might work

18
00:00:56.320 --> 00:01:00.928
Is the ray tracing for example determines the absorption of light within the silicon

19
00:01:01.440 --> 00:01:04.256
It may even give you something like the generation profile

20
00:01:04.512 --> 00:01:07.328
And then you can load that into those other programs

21
00:01:08.352 --> 00:01:12.192
The advantage of doing this is that they have more complicated electrical models

22
00:01:12.448 --> 00:01:13.728
There's a lot more inputs that you might

23
00:01:13.984 --> 00:01:16.032
Set there so for example

24
00:01:16.288 --> 00:01:22.432
If you want to understand how the recombination underneath the metal fingers affects the voltage of the cell this is the type of

25
00:01:22.688 --> 00:01:23.712
Approach you would take

26
00:01:24.224 --> 00:01:27.552
The Ray tracing will tell you the generation profile within the silicon

27
00:01:27.808 --> 00:01:30.624
And that can be then used as an input into those other solvers

28
00:01:31.136 --> 00:01:35.488
The disadvantage of course is that it requires the integration of two separate computer programs

29
00:01:36.256 --> 00:01:38.304
And this approach is not always necessary

30
00:01:40.096 --> 00:01:41.376
SunSolve itself

31
00:01:41.632 --> 00:01:43.680
Also has an integrated electrical solver

32
00:01:43.936 --> 00:01:45.984
Based on an equivalent Circuit model

33
00:01:46.240 --> 00:01:50.080
The different parts of the software link together to set up that model

34
00:01:50.592 --> 00:01:55.200
And then based on this we can convert our optical output into an electrical

35
00:01:55.456 --> 00:01:55.968
Output

36
00:01:56.480 --> 00:01:59.040
This allows for some electrical loss analysis

37
00:01:59.296 --> 00:02:01.088
And it's also compatible with doing

38
00:02:01.344 --> 00:02:02.624
Yield simulations

39
00:02:03.136 --> 00:02:05.696
The advantages are that it's a single simulation tool

40
00:02:05.952 --> 00:02:06.976
It's very fast

41
00:02:07.488 --> 00:02:10.304
The disadvantage is that it's a somewhat simplified electrical model

42
00:02:11.328 --> 00:02:12.352
Let's take a little bit

43
00:02:12.608 --> 00:02:14.144
Closer look at how that works

44
00:02:14.656 --> 00:02:16.960
The Ray tracing can be combined with

45
00:02:17.216 --> 00:02:18.496
The collection efficiency

46
00:02:18.752 --> 00:02:20.544
And the spectrum of light that's been chosen

47
00:02:21.056 --> 00:02:24.640
And this then feeds into the light generated current source of that

48
00:02:24.896 --> 00:02:25.664
Equivalent circuit

49
00:02:27.968 --> 00:02:34.112
There's also a grid simulation within the program which is going to calculate the different parts of the series resistance and that can also be

50
00:02:34.368 --> 00:02:36.160
Used as part of this equivalent Circuit

51
00:02:37.696 --> 00:02:41.024
The parasitic losses in the middle there need to be set by the user

52
00:02:41.280 --> 00:02:42.816
And there's a couple of ways that we can do that

53
00:02:46.400 --> 00:02:48.192
For crystalline silicon solar cells

54
00:02:48.448 --> 00:02:54.592
This equivalent Circuit model is surprisingly good at reproducing the output power of the cells and modules as a function of illumination

55
00:02:54.848 --> 00:02:56.128
Intensity and temperature

56
00:02:57.408 --> 00:03:00.992
These equivalent circuits can also be brought together within the module itself

57
00:03:01.504 --> 00:03:02.272
In this case

58
00:03:02.528 --> 00:03:05.344
Each cell is represented by its own equivalent Circuit

59
00:03:05.856 --> 00:03:09.184
The ray tracer determines the light generated current in each cell

60
00:03:09.440 --> 00:03:11.488
Which could be non uniform for a number of reasons

61
00:03:12.512 --> 00:03:15.328
A spice solver is then used to bring all these circuits

62
00:03:15.584 --> 00:03:17.120
And some bypass diodes together

63
00:03:17.376 --> 00:03:19.936
To provide the output characteristics of the module

64
00:03:20.960 --> 00:03:21.728
SunSolve

65
00:03:22.240 --> 00:03:24.032
Quantifies the mismatch loss

66
00:03:24.288 --> 00:03:25.568
By solving this twice

67
00:03:25.824 --> 00:03:27.872
It does it once with all the cells connected

68
00:03:28.128 --> 00:03:29.408
And it does it a second time

69
00:03:29.664 --> 00:03:30.944
With the cells disconnected

70
00:03:31.200 --> 00:03:33.248
Summing up the maximum power of each cell

71
00:03:33.760 --> 00:03:35.296
This provides some sort of a metric

72
00:03:35.552 --> 00:03:36.576
For the mismatch loss

73
00:03:38.880 --> 00:03:43.488
Now let's have a look at how we would set those electrical inputs within the SunSolve user-interface

74
00:03:44.000 --> 00:03:46.816
To demonstrate that I'm going to use a full module template

75
00:03:47.328 --> 00:03:50.400
And let's choose the 72 cell bi-facial module

76
00:03:51.424 --> 00:03:52.448
The previous video

77
00:03:52.704 --> 00:03:53.216
Showed

78
00:03:53.728 --> 00:03:56.800
How we would set some of these optical inputs on a layers tab

79
00:03:57.056 --> 00:04:00.128
For the electrical inputs we're going to go across to the circuit tab

80
00:04:00.896 --> 00:04:03.456
Here you can see the equivalent circuit that we've been talking about

81
00:04:03.968 --> 00:04:07.296
You can switch the different components in and out of the simulation by clicking on them

82
00:04:08.064 --> 00:04:10.624
And you can adjust the input values over here

83
00:04:11.392 --> 00:04:14.976
Like a lot of inputs in SunSolve you're able to click on the units to change them

84
00:04:15.744 --> 00:04:18.815
You'll noticed the light generated current doesn't have a value yet

85
00:04:19.071 --> 00:04:20.863
That's because it needs the ray tracing result

86
00:04:21.375 --> 00:04:24.191
Once it gets that Ray tracing result it's going to combine it

87
00:04:24.447 --> 00:04:26.495
With the collection efficiency you can see up here

88
00:04:27.263 --> 00:04:27.775
There's a

89
00:04:28.031 --> 00:04:31.359
Separate collection efficiency for the front and the rear of the cell

90
00:04:31.871 --> 00:04:34.175
The way this works is during the Ray tracing

91
00:04:34.431 --> 00:04:35.711
When light enters the module

92
00:04:36.479 --> 00:04:37.759
The ray tracer remembers

93
00:04:38.015 --> 00:04:39.039
Whether it entered the

94
00:04:39.295 --> 00:04:39.807
Cell

95
00:04:40.063 --> 00:04:41.343
From the front side

96
00:04:41.599 --> 00:04:42.879
Or whether the light

97
00:04:43.135 --> 00:04:45.951
maybe passed between the cells and entered from the rear

98
00:04:47.231 --> 00:04:50.815
It will then apply the two different collection efficiencies to get the final current

99
00:04:51.327 --> 00:04:54.655
This allows for more accurate bi-facial simulations

100
00:04:57.471 --> 00:05:00.287
You'll notice there's also an option to solve the series resistance

101
00:05:00.799 --> 00:05:01.311
You can

102
00:05:01.567 --> 00:05:02.335
Disable that

103
00:05:02.591 --> 00:05:04.383
And just at the series resistance yourself

104
00:05:04.895 --> 00:05:05.407
Or

105
00:05:05.663 --> 00:05:06.687
If you want to use that

106
00:05:06.943 --> 00:05:08.735
You need to come across to the electrodes tab

107
00:05:09.503 --> 00:05:14.623
You can see here all the different inputs that define the Geometry of those electrodes

108
00:05:15.135 --> 00:05:17.951
You can preview that by clicking on that button there

109
00:05:19.231 --> 00:05:21.023
This geometry is used for

110
00:05:21.279 --> 00:05:22.303
The optical solving

111
00:05:22.815 --> 00:05:24.607
But it's also used for the electrical solving

112
00:05:25.119 --> 00:05:26.399
It combines the

113
00:05:26.655 --> 00:05:28.959
Cross-sectional areas with the resistivity

114
00:05:29.215 --> 00:05:29.983
From this table

115
00:05:30.495 --> 00:05:32.543
To determine the series resistance losses

116
00:05:33.567 --> 00:05:35.615
There's also contact resistance that you can set

117
00:05:35.871 --> 00:05:37.663
And there's a few of the internal elements

118
00:05:38.175 --> 00:05:40.223
That can also be used so for example

119
00:05:40.479 --> 00:05:42.527
We can enable the front skin solving

120
00:05:42.783 --> 00:05:46.367
And this would give us the ability to set a resistive element

121
00:05:46.623 --> 00:05:47.903
Similar to a

122
00:05:48.159 --> 00:05:51.231
Emitter sheet resistance or perhaps an ITO layer

123
00:05:51.743 --> 00:05:57.887
This can be useful if for example your sweeping the number of fingers and you want the series resistance to adjust itself

124
00:05:58.655 --> 00:05:59.935
For each value that you

125
00:06:00.191 --> 00:06:00.959
Simulate

126
00:06:03.263 --> 00:06:05.567
So this is the equivalent Circuit for

127
00:06:05.823 --> 00:06:07.103
A single solar cell

128
00:06:08.127 --> 00:06:10.431
We can also have a look at how those are laid out

129
00:06:10.687 --> 00:06:11.711
In the complete module

130
00:06:13.247 --> 00:06:13.759
This

131
00:06:14.015 --> 00:06:20.159
Area here allows us to change that layout we've got some standard layouts you can use or you can also manually

132
00:06:20.415 --> 00:06:20.927
Adjust that

133
00:06:21.183 --> 00:06:24.255
And that will update the layout for the optical Solver as well

134
00:06:25.023 --> 00:06:29.375
We also include bypass diodes there's a simple model for those that you can set here

135
00:06:29.631 --> 00:06:31.935
If you want to remove them you can click on them like that

136
00:06:33.215 --> 00:06:35.519
So let's go ahead and run this module

137
00:06:37.823 --> 00:06:42.431
And you'll notice that when we press run the first thing that solves is actually that grid solver

138
00:06:42.687 --> 00:06:46.271
So now we have a calculated value for the grid resistance

139
00:06:46.783 --> 00:06:51.135
And we also have the ability to add an additional amount of resistance if you didn't want to use that

140
00:06:51.391 --> 00:06:52.671
You could just set it to 0

141
00:06:53.951 --> 00:06:54.463
Now

142
00:06:54.975 --> 00:07:01.119
A lot of the inputs lock themselves once the ray tracer has run however for the electrical circuit

143
00:07:01.375 --> 00:07:03.935
You're able to continue to change those afterwards

144
00:07:04.191 --> 00:07:05.727
So there's no need to

145
00:07:05.983 --> 00:07:08.031
Rerun the ray tracer as you're

146
00:07:08.799 --> 00:07:11.871
Adjusting your electrical inputs, you can keep changing those

147
00:07:12.127 --> 00:07:14.943
And the electrical Solver will

148
00:07:15.199 --> 00:07:16.223
Rerun itself

149
00:07:16.479 --> 00:07:17.503
That includes

150
00:07:17.759 --> 00:07:21.087
Setting this collection efficiency and adjusting those JL values

151
00:07:23.135 --> 00:07:24.927
So now let's have a look at the output

152
00:07:25.951 --> 00:07:27.487
This was the optical output

153
00:07:27.999 --> 00:07:29.791
We can come across here to the module output

154
00:07:30.047 --> 00:07:34.911
Now we can see a table which has the basic IV parameters in it

155
00:07:35.167 --> 00:07:37.215
That's shown for the complete Circuit

156
00:07:37.471 --> 00:07:39.519
Also for the case where

157
00:07:40.031 --> 00:07:44.639
The cells are solved individually and allowed to get to their maximum power point

158
00:07:46.431 --> 00:07:48.223
Down here is the IV plot

159
00:07:48.479 --> 00:07:53.087
And like a lot of the graphs in SunSolve you can just copy that figure data onto the

160
00:07:53.599 --> 00:07:55.647
Clipboard and then paste it into Excel

161
00:07:57.439 --> 00:08:00.255
Here we also have the per cell output

162
00:08:01.279 --> 00:08:02.047
This heat map

163
00:08:02.303 --> 00:08:06.143
Is showing us the light generated current within each of the cells

164
00:08:06.399 --> 00:08:08.191
It's important to remember

165
00:08:08.447 --> 00:08:11.519
That is the light generated current and it's not the actual current

166
00:08:11.775 --> 00:08:12.799
In the Solar cell

167
00:08:13.311 --> 00:08:14.847
Since they're all connected that would be

168
00:08:15.103 --> 00:08:15.615
The same

169
00:08:16.383 --> 00:08:21.759
Now this is where it becomes important to make sure we set the correct number of rays for the simulation

170
00:08:22.015 --> 00:08:24.319
The random nature of the ray tracer means that

171
00:08:24.575 --> 00:08:25.855
If we don't use enough rays

172
00:08:26.111 --> 00:08:27.903
We don't get enough of a

173
00:08:28.159 --> 00:08:30.207
Uniform distribution across the module

174
00:08:30.463 --> 00:08:32.767
And we end up with some cells like this one here being

175
00:08:34.047 --> 00:08:34.559
Much

176
00:08:34.815 --> 00:08:38.143
Higher in the light generated current than the cells around it

177
00:08:38.655 --> 00:08:39.935
So you'll find that with

178
00:08:40.447 --> 00:08:43.775
The module simulations you'll probably going to need to use

179
00:08:44.031 --> 00:08:45.567
Millions of rays to

180
00:08:45.823 --> 00:08:47.615
Remove that otherwise you'll get

181
00:08:47.871 --> 00:08:50.943
An excessive amount of mismatch loss in the cells

182
00:08:52.223 --> 00:08:55.295
So let's let that one solve and we should see that we get a much more

183
00:08:55.807 --> 00:08:59.135
Correct distribution ofthe cell generated current

184
00:09:01.183 --> 00:09:02.207
Within the module

185
00:09:05.535 --> 00:09:10.399
So that's been a basic overview of the electrical solver within SunSolve

186
00:09:11.423 --> 00:09:12.191
And

187
00:09:12.447 --> 00:09:13.727
You can download

188
00:09:14.495 --> 00:09:16.031
Those parameters

189
00:09:16.543 --> 00:09:20.639
Over here with the export outputs you can see that we have the electrical summary

190
00:09:20.895 --> 00:09:22.175
Or the electrical curve data

191
00:09:22.687 --> 00:09:28.831
There's also specialised outputs if you want to link that optical result to the Quokka solver

192
00:09:29.087 --> 00:09:30.111
Or the Griddler solver

193
00:09:31.135 --> 00:09:34.719
So that's the basic overview of how the electrical solver works

194
00:09:34.975 --> 00:09:35.999
I hope you found this useful